I've done a few things around here to reduce my "carbon footprint" and that of my family...
I recently decided to just keep it at the forefront of my mind for a while to turn the lights off in the house. During the day now, I keep ALL the lights off, unless I need them. In a matter of just a few weeks, I actually notice if lights are left on, instead of not noticing at all.
The other thing I've tried to do more and more is not to bring anymore plastic bags home with me when I go shopping. One by one, I've bought a bag or two at each of the stores I visit, so I have one or two from Target and Safeway, a couple from Trader Joe's (they're the nicest -- canvas!) and a couple from Roth's, and a couple from Albertsons. I finally have enough to cover pretty much any trip to any store, and I use them everywhere -- not just groceries like yesterday, but also Target, and the fabric store where I bought some fabric on sale to make my own curtains.
It's amazing how many people are starting to do this too. What was hardest for me was remembering them. Often, they'd be in the back of the car, but I'd get into the store and realize I'd forgotten them! With a baby in the cart, you can't just dash out and get them, so I'd just get plastic and feel guilty about it.
Finally, I decided that if I'm leaving the house with a list to buy things, I automatically put the cloth bags in the FRONT seat of the car, along with the diaper bag and my purse. That way I don't forget!
We have a lot of plastic bags to use for garbage bags and cat litter box bags, and until they're gone, I'm going to do my best not to bring any more into the house!